Learn how a Roth conversion is taxed, how IRA basis and the pro-rata rule work, which forms report it, and what California taxpayers should know.
A Roth conversion moves retirement assets from a pretax traditional IRA, SEP IRA, SIMPLE IRA, or eligible employer plan into a Roth IRA or designated Roth account. The converted amount is generally included in income to the extent it has not already been taxed. The conversion itself is generally exempt from the 10% early-distribution additional tax, but withholding or later withdrawals can create penalties.
A conversion is different from a regular Roth IRA contribution. It does not use the annual IRA contribution limit, and the income limits that restrict regular Roth contributions generally do not prohibit a conversion.
The taxable amount is not automatically the cash moved. Pretax contributions and earnings are generally taxable; valid after-tax basis is not taxed again. A conversion from a qualified employer plan may include separately tracked pretax and after-tax amounts. A conversion from traditional, SEP, or SIMPLE IRAs uses Form 8606 and the IRA aggregation or pro-rata rule.
Example: Jordan has $20,000 of nondeductible traditional-IRA basis and $80,000 of total value across all traditional, SEP, and SIMPLE IRAs on December 31. Jordan converts $20,000 during the year and takes no other distribution. Using a simplified illustration, 25% of the conversion represents basis:
$20,000 basis ÷ $80,000 total IRA value = 25% tax-free ratio
$20,000 conversion × 25% = $5,000 nontaxable basis recovery
$20,000 − $5,000 = $15,000 generally taxable conversion
Jordan cannot choose only the "after-tax account" and ignore other traditional, SEP, or SIMPLE IRA balances. Year-end value, distributions, rollovers, outstanding rollovers, and prior basis affect the actual Form 8606 calculation.
A trustee-to-trustee conversion moves funds directly from a traditional IRA to a Roth IRA. A plan-to-Roth-IRA conversion can use a direct rollover from an eligible employer plan. An in-plan Roth rollover moves eligible amounts from a plan's pretax account to its designated Roth account when the plan permits it.
A direct method generally reduces withholding and deadline risk. If money is paid to the taxpayer, rollover rules, mandatory withholding for eligible employer-plan distributions, and the 60-day deadline may apply. Any amount withheld and not replaced is generally treated as a distribution rather than converted.
Required minimum distributions are not eligible for rollover or conversion. A taxpayer who must take an RMD generally takes it first, then converts other eligible amounts.
The distributing institution generally issues Form 1099-R, and the receiving Roth IRA custodian generally reports the receipt on Form 5498. Form 8606 reports conversions from traditional, SEP, and SIMPLE IRAs and calculates taxable and nontaxable portions. Employer-plan conversions can follow different reporting paths.
A taxable conversion increases adjusted gross income. It can affect Medicare income-related premiums, the Net Investment Income Tax threshold, premium tax credits, education benefits, taxation of Social Security, estimated tax, and California tax. It does not create wages or self-employment income.
Conversions made in 2018 or later generally cannot be recharacterized back to a traditional IRA. A regular IRA contribution may still be recharacterized when eligible, but that is not the same as undoing a completed conversion. Market decline after the conversion does not reduce the income originally recognized.
Because the decision is generally irrevocable, taxpayers sometimes use partial conversions over several years. The right amount depends on current and expected future tax rates, deductions, cash available to pay tax, age, beneficiaries, RMD exposure, charitable plans, and state residency.
Roth IRAs have more than one five-year rule. One helps determine whether earnings are part of a qualified tax-free distribution. A separate five-year period generally applies to each conversion when determining whether an early withdrawal of converted taxable amounts triggers the 10% additional tax before age 59½.
Conversion principal is not taxed again when withdrawn, but ordering rules and the separate conversion clocks still matter. Paying the conversion tax from outside funds often preserves more retirement value and avoids treating withheld retirement money as an unconverted distribution.
California generally taxes the same pretax portion of a Roth conversion that is federally taxable. Historical California basis can differ from federal basis, however, especially when prior IRA deductions differed. Preserve Forms 8606, Schedules CA, FTB Publication 1005 worksheets, Forms 1099-R, and year-end statements.
California does not generally impose an additional tax merely because a valid conversion occurred. Amounts withheld or distributed rather than converted can produce a different result. California also does not conform to every federal Roth-related provision; special transactions such as 529-plan-to-Roth-IRA rollover treatment require separate state analysis.
Heath Income Tax can help project a conversion, reconcile IRA basis, and report its federal and California effects.
Is there an income limit for a Roth conversion?
Federal law generally does not impose the regular Roth-contribution income limit on conversions. Taxability and suitability still require analysis.
Is a Roth conversion subject to the 10% penalty?
The amount properly converted is generally exempt. Amounts withheld or not completed as a conversion may be subject to tax and penalty, and early withdrawals of conversion amounts have separate five-year rules.
Can I convert only my nondeductible IRA contribution?
Not simply by selecting that account. Form 8606 generally aggregates traditional, SEP, and SIMPLE IRAs and allocates basis pro rata.
The definitions and examples on this page are for informational purposes only and do not constitute tax advice. Tax laws change frequently and individual circumstances vary. Consult a qualified tax professional before making decisions based on this content.
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